Abstract: In order to study effect of spinal cord granule I (SCI) on calcitonin gene related peptide (CGRP) expression in dorsal root ganglia (DRG) after spinal cord injury and to inquire into mechanism of promoting spinal cord regeneration in rats with SCI, effect of SCI on CGRP expression in DRG of Wistar rats subjected to right hemisection at the lower thoracic spinal cord were evaluated by immunocytochemistry and quantitative image analysis. The results are followed as: ① A significant down regulation of CGRP expression in ipsilateral 3 DRG oral and caudal to the injury level was caused by spinal cord hemisection respectively. The down regulation of CGRP expression is consistent and no reversed during one month after spinal cord injury. ② The down regulation of CGRP expression was evidently relieved but not prevented with administration of SCI. ③ The down regulation of CGRP expression induced by spinal cord injury was not relieved with administration of Buyang huanwutang or hydrocortisone in a large doses. ④The spinal tissue injured was repaired and regenerated in rats with administration of SCI. So that, the results not only suggested a possibility that reversion of CGRP expression following down regulation may be as a mark for regeneration of spinal cord tissue injured, but also indicated that it may be one of mechanisms for promoting repair and regeneration of spinal cord injured that SCI regulates CGRP mRNA expression.

Key words: Chinese herb, spinal cord regeneration, dorsal root ganglia, CGRP expression